Multispectroscopic and molecular docking studies on the interaction of diltiazem hydrochloride with bovine serum albumin and its application to the quantitative determination of diltiazem hydrochloride
Nafisur Rahman, Nabila Khalil, Sumaiya Khan, Mikhlid H. Almutairi, Bader O. Almutairi, Mahboob Alam
Abstract
The interaction between diltiazem hydrochloride (DTZ) and bovine serum albumin (BSA) was probed by fluorescence, UV–vis absorption, Fourier transform infrared, circular dichroism spectroscopies and molecular docking analysis at pH = 7.4. The decrease in Stern-Volmer quenching constants with rising temperature illustrated the static nature of fluorescence quenching. The distance between DTZ and BSA was evaluated and found to be 1.40 nm. The thermodynamic parameters such as ΔG, ΔH and ΔS were computed which illustrated the spontaneous and endothermic nature of binding of DTZ with BSA. Molecular docking evaluation indicated that DTZ fits into the binding pocket of subdomain I-B (site III). A spectrofluorimetric method was developed based on fluorescence quenching of BSA by DTZ to quantify diltiazem in tablets.